Para-acetylbenzyl compounds



Patented Apr. 6, 1948 PARA-ACETYLBENZYL COMPOUNDS William S. Emerson,Dayton, Ohio, assignor to Monsanto Chemical Company, St. Louis, Mo,

acorporation of Delaware No Drawing. Application June 1946, Serial No.678,672

9 Claims. (01. 260-488) Thepresent invention-relates to newpara-substituted benzylcompoundsand'to the preparation of suchmaterials.= It provides an efiicient and inexpensive methodiwherebypara-acetylbenzyl acetate may b'ederived from para-ethylbenzyl acetate.This is particularly valliable in that the latterimaterial may 'besecured through para-ethylbenzyl chloride from ethylbenzene,

which has become a convenient source material.-

Anobjectof the invention'is to provide materials usable as intermediatesfor the production of polymeric subs'tancesgaszis disclosed in mycopending application Serial No. 678;673, filed June 22, 1946. Thiscarrfe's th'epara-(alpha-oxyethybb'enzyl acetateprodu'ct of the-instantcase to para-vinylbenzyl acetate.

The following examples illustrate an embodiment of the preparation andproperties of the chemical compounds which-comprise the instantinvention.

Pam-ethylbenzyl chloride-In a one-liter, i3- necked flask,equipped witha stirrer, thermometer, gas inlet and reflux condenser, wereplaced 800cc. of ethylbenzene, 600g; of paraformaldehyde, and 40 g. of fused andpulverized zinc chloride. While this mixture was stirred as vigorouslyas possible and the internal temperatur was held at 66-69 a vigorousstream of hydrogen chloride was introduced until the mixture wassaturated. At this point-the flow was moderated so that hydrogenchloride evolved slowly from the top of thecondenser; The total reactiontime was one hour. Thehydro'gen chloride flow was then stopped and thereaction mixture cooled to 25. After pouring into a one-liter separatoryfunnel the mixture was separated'into twolayers and the ethylbenzene wastransferred to "another separatory tunnel to fieeit from any zincchloride adhering to the sides of thebriginal funnel.

The ethylbenzene solution was washed six times with water and then driedover sodium sulfate. Distillation yielded 222 g. (71% based onformaldehyde) of para-ethylbenzyl chloride, B. P: 94-- 100 C./11 mm.(literature value 106-110/15 mm), 11 1.5293.

Pam-ethylbenzyl acetate-A mixture of 110 g. of fused sodium acetate, 800cc. of glacial acetic acid and 223 g. of para-ethy-ibenzyl chloride wasrefluxed for 30 minutes. Upon cooling, the precipitated sodium chloridewas removed by filtration, washed with 200 cc. of glacial acetic acid,and these washings together with 25 g. of fused sodium acetate wereadded to the filtrate. This was then refluxed for an additional 2 hoursbefore dilution with water and removal of the product by benzeneextraction. Distillation of this extract yielded 238 g.- (93%) ofpara-ethylbenzyl acetate, B. P. 117-127 C./14 mm., n 1.5018. Ananalytical sample of the compound boiled at 130-132 C./15 mm., 111.5042,

Anal: Calcdior C11H14O2: C, 74.3; H, 7.816..

Found: C, 73.9; H, 7.91. Para-acetylbenayl acetate-A vigorous stream ofair was introduced through an .alundum dis-- perser into a mixture of485 g. of para-ethylbenzyl acetate, 5 g. of chromium oxideand 20 g. ofcalcium-carbonate held at 130-140 for 28 hours.

Upon cooling, the catalyst was removed by filtration and the filteredproduct was then refluxed for two hours with 10 g. of sodium acetate and100 cc. of acetic anhydride: After dilution with water, the product wasextracted with benzene and distilled to give 287 g. (59% recovery) ofparaethylbenzyl acetate, B. .P. 119-129/12 mm., 1.5011 and 118 g. (23%conversion and 55% yield) of para-acetylbenzyi acetate, B. P; 155- 185at 12 mm.; 11 1.5225. Ananalytical sample boiled at161-163/11 mmp, n1.5225,

'AnaL: CalcdjforCriHmOs: C. 68.8; H, 6.25.

Found: C, 68.9; H, 6.66.

The 2,4-dinitrophenylhydrazone melted at 182- 183 after onecrystallization from ethyl acetate.

AnaL: Calcd. for C17H1606N4i N, 15.1.

Found: N, 15.0.

The semicarbazone was crystallized twice from 50% alcohol and twice fromalcohol, M. P. 186-167 C. i i

Anal: Calcd. for CizHisosNs: C, 57.8; H, 6.02; N, 16.9.

Found: C, 58.0;H,'6.05; N, 16.9.

' Para-(aZpha-hydroxyethyl)benayl acetate.-A mixture of 215 g. ofpara-acetylbenzyl acetate and 25 g. of copper chromite was shaken forsix hours in standard equipment with hydrogen at an initial pressure of2000 pounds. Reduction was eiiected at -155. Upon cooling, the chargewas removed from the bomb, filtered and the precipitate washed withbenzene. Distillation of the filtrate yielded 184 g. (85) of crudepara-(alphahydroxyethyDbenzyl acetate, B. P. 135-'160/3 Para-(aZpha-acetoxyethyl) benzyl acetate-A mixture of '48 g. of crudepara-(alpha-hydroxyfor three hours and then allowed to stand overnight.The acetic anhydride was then distilled until the volume of the residuewas reduced to 200 cc. before dilution with one liter of water. After ithad stood one hour it was extracted three times with benzene. Thecombined extracts were washed three times with water. Distillationyielded 44 g. (75%) para-(alpha-acetoxyethyl)- benzyl acetate, B. P.144-153/3 mm., n 1.4998, d: 1.114

Anal: Calcd. for Cpl-11504: C, 66.1; H, 6.78; sap. equiv. 115.

Found: C, 66.0; H, 6.73; sap. equiv. 125, 123.

Specifically this invention provides the'new .compound corresponding tothe formulae:

para-acetylbenzyl acetate, and

para-(alpha-hydroxyethyl)benzyl acetate, which are particularly valuableas intermediates for the production of polymeric materials.

The oxidation step to produce para-acetylbenzyl acetate may be carriedout at atmospheric pressure or vacuum and even at moderate pressures,but I have discovered that the use of excessive pressure is detrimentalin that the reaction will, under such conditions, proceed to a resinousform immediately andquantitatively.

The oxidation is carried out in the liquid phase by means of anoxygen-containing gas applied in the presence of an oxidizing catalyst.While the preparation of para-acetylbenzyl acetate from para-ethylbenzylacetate has beenv described as occurring in the presence of a chromiumoxide catalyst, I have found that any metal oxide or hydroxide may beused in place of the chromium oxide specifically described. Theparticularchromium oxide catalyst which I have found to be particularlyeflicacious is a mixture of this material with calcium carbonate in theweight ratio of 1:14. While I prefer to use air as the oxidizing medium,I may use pure oxygen or a prepared mixture of oxygen with an inert gasTemperatures between 110 and 160 C. are suitable for reaction to beeffected.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results obtained.

Since many changes could be made in the above methods and productswithout departing from the scope of the invention, it is intended thatall matter contained in the above description shall be interpreted asillustrative and not in a limiting sense and that the invention is to beconstrued broadly and restricted solely by the scope of the appendedclaims.

What I claim is:

1. The compounds having the formula:

cmcomm-O-x where X is selected from the class consisting of and " 2. Thecom-pound para-acetylbenzyl acetate- 3. The compoundpara-(alpha-hydroxyethyl) benzyl. acetate.

'4. The process for producing para-acetylbenzyl acetate which comprisescontacting para-ethylben'zyl acetate in the liquid phase with gaseousoxygen in the presence of an oxidation catalyst.

5. The process defined'in claim 4 in which the oxidation catalyst.comprises CrzOs.

6. The process? for producing para-acetylbenzyl acetate which comprisescontacting para-ethylbenzyl acetate in. the liquid phase with gaseousoxygen in the presence of an oxidation catalyst comprising a mixture ofCH0: and CaCOz.

7. The process defined in claim 6 in which the oxidation catalystconsists of four parts by weight of CaCOs and one part by weight ofCrzOs.

8; The process defined in claim 6 in which the oxidation catalyst iscarried out at temperatures between C. and C.

9. The process for producing para-acetylbenzyl acetate which comprisescontacting para-ethylbenzyl acetate in the liquid phase with air in thepresence of an oxidation catalyst comprising a mixture of one part ofC12O3 and four parts of CaCOs at a temperature between 110 C. and 160 C.

WILLIAM S. EMERSON REFERENCES CITED The following references are ofrecord in the file of this patent:

UNITED sense- PATENTS Number Name Date 2,156,721 Simo et al. May 2, 19392,302,466 Palmer et a1 Nov. 17, 1942 2,376,674 Emerson et al. May 22,1945 Hockwalt Dec. 4, 1945 OTHER REFERENCES

